The effects of high temperatures (29–123 °C) on critical micelle concentrations in solutions of potassium n-octanoate in deuterium oxide: A nuclear magnetic resonance study

Abstract

M. A. DESANDO and L. W. REEVES. Can. J . Chem. 64, 1823Chem. 64, (1986. Critical micelle concentrations have been determined for potassium n-octanoate in deuterium oxide over a wide temperature range, 29-123"C, from the concentration dependence of proton nmr spectral parameters (peak positions, and vicinal splitting values of the a-CH2 multiplet) and carbon-13 nrnr chemical shifts. The c.m.c. varies from ca. 0.30 m at ca. 30°C to ca. 0.50 m at ca. 120°C and is at a minimum (0.30-0.35 m) in the temperature range ca. 30-50°C. 2 3~a + spin-lattice relaxation times reveal that a co-counterion (Na') different from that of the surfactant counterion (K') reflects the micellization process. A second critical micelle concentration has been observed around 1.0 m at ca. 30°C. dans l'intervalle de tempkrature de 30 2 50°C. Lcs temps de relaxation spin-rCseau du 2 3~a -rkvelent que la pyCsence d'un contre-ion (Na') diffkrent de celui prCsent dans les surfactants (K-) se rkflete dans le processus de micellisation. A 30°C, on a aussi observC une deuxieme concentration micellaire critique autour de 1.0 rn.[Traduit par la revue]

Water proton NMR—a sensitive probe for solute association

“…Both sets of data are scattered, consistent with published chemical shift data of the same two sets of protons in KC 8 micellization. 11 The C 2 methylene proton chemical shift profile displays two turning points matching, respectively, the 1st and 2nd reported critical micelle concentrations (CMCs) of NaC 8 . The C 8 methyl proton chemical shift profile displays only one hardly visible turning point near the 1st reported CMC of NaC 8 .…”

NMR Spectroscopy and the Effects of Enantiomerism on the Micelle Formation of PotassiumN-n-Dodecanoylalaninate

“…37ЊC and 20.12 because of its relevance to the nature of chirality in biochemical systems and its application to catalytic processes (13). MHz on a Bruker WP-80 spectrometer operating in the Fourier transform mode with deuterium lock from the solvent, In addition, potassium N-n-dodecanoylalaninate provides a test for the measurement of very low cmc values by carbon-were obtained as described in previous publications (15,16), Fourier-transformed proton magnetic resonance spectra of 13 NMR spectroscopy and the comparison of results with data from proton magnetic resonance spectra.…”

“…3). The (CH 2 ) 6 resonance was used to determine the cmc values reported in Table 1, as it is the most intense Concentration-dependent NMR spectra of potassium Nn-dodecanoylalaninate reveal that micelle formation indeed band in the surfactant carbon-13 NMR spectrum, and thus is a property of the isotropic solutions, as is the case with an aqueous solvent, e.g., cmc Å 0.0122 m for dodecylpyriother surfactants (2,15,16). Plots of d versus 1/C T often dinium bromide in water at 35ЊC (21).…”

Temperature-dependent anomalous viscosity of aqueous solutions of imidazolium-based ionic liquids

“…With the variation of temperature, the critical micelle concentration (CMC) of amphiphilic molecules changes. 93,94 For ILs with increasing temperature, it first decreases to reach a minimum and then increases. 95 All the reported values of CMC of ILs are much higher than the CMC of sodium dodecyl sulfate (SDS), which is a well-known charged surfactant.…”